1. Field
Embodiments relate to an organic light emitting diode (OLED) display and a method of driving the same.
2. Description of the Related Art
Display devices are used as a display device of a portable information terminal such as a personal computer, a mobile phone, and a personal digital assistant (PDA) and a monitor of various information devices and have been known as an a liquid crystal display (LCD) using a liquid crystal panel, an OLED display using an organic light emitting element, and a plasma display panel (PDP) using a plasma panel. In the display devices, the OLED display having excellent light emitting efficiency, luminance, and viewing angle and a fast response speed has been in the spotlight.
The OLED display disposes a plurality of pixels in a matrix format on a substrate to form the pixels in a display area, and connects a scan line and a data line to each pixel to selectively apply a data signal to the pixel, thereby displaying an image. Such an OLED display may be classified into a passive matrix OLED display that forms to cross a positive electrode and a negative electrode and that selects and drives a line and an active matrix OLED display that maintains a data signal that is switched by a switching transistor with a capacitor and that applies the data signal to a driving transistor and that thus controls a current flowing to an OLED.
However, in the active matrix OLED display, due to a process errors, threshold voltage Vth characteristics of a driving transistor may be differently displayed according to a position of a display area. In this case, even if the same data signal is applied to a driving transistor of each pixel, a difference exists in a current flowing to the OLED, and resultantly each pixel emits light with different luminance.
That is, when a threshold voltage deviation of a driving transistor occurs between pixels within a display panel, a uniformity failure and a stain of luminance are viewed. Moreover, when a deviation of a threshold voltage of such a driving transistor occurs between display panels, a gray voltage of different black levels or white levels occurs according to a panel and thus a characteristic of luminance and a contrast ratio of each display panel are not uniform. In order to solve this, an optical compensation method of correcting a data signal according to gamma characteristics of the OLED display is applied.
The above information disclosed in this Background section is only for enhancement of understanding of the background and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.